54 ICHNOGRAPHS OF THE 



mining the organization of the sandstone animals. Among the multitude of foot- 

 prints, not one, in thousands of them, presents the impress of the tegumentary 

 papillae of the toes. In the great number I have studied, I have seen very 

 few examples, and one of them is the photograph Plate 16. However perfect 

 the impression, the pressure of the toes has produced only a smooth, unbroken 

 surface. The absence of this feature is certainly a negative proof against an 

 ornithic origin. It might be supposed that buds so gigantic as those to which 

 these impressions are ascribed, if they were fitted to traverse the land, would 

 'possess the same organizations as occur in existing types. The smoothness of 

 the dermoid coverings of the toes would of itself indicate that the animals were 

 constituted for the water rather than the land. In the fine photograph, Plate 

 1G, the style of the dermoid markings does not correspond to that of existing 

 land birds. The integuments appear to be marked in fine lozenge-shaped checks, 

 and not by those round, prominent points that characterize the feet of terrestrial 

 birds. It might, however, be supposed that the impress of such minute bodies 

 would not be retained by the materials of the stratum ; but the most delicate 

 objects, as the feet of insects and the minute rays of fishes' fins, are accurately 

 preserved. 



To the above remarks by Dr. Deane we will add. that Plate 33 represents the species 

 described by Dr. Hitchcock as the Plesiomis quadrupes. Plate 34, figs. 1 and 2, 

 represent impressions of the animal described by Dr. Hitchcock as the Apatichnus 

 circumagens. The specimens are in the collection of Roswell Field, Esq. 



PLATES XXXV. AND XXXVI. 



Like the footprints upon the four preceding Plates, those upon Plate 35 are 

 also of compound character, tridactylous behind and reptilian before. They indicate 

 animals of unknown type. It is evident that they moved by crawling. The 

 posterior foot is analogous to the feet of some living birds, and does not differ 

 from those sandstone footprints that have been described as due to birds. The 

 anterior foot has four toes, and is reptilian in its character. It points outward, 

 and falls, in walking, a little in advance of the posterior foot. The relative 

 positions of the right and left feet vary essentially from those of the preceding 

 Plates. In Plates 33 and 34, the feet fall, in walking, in a direct line nearly, 

 while the right and left feet, in Plate 35, are broadly separated. All the feet 



